In a conventional image forming apparatus using an electrophotographic image forming process, a process cartridge type in which the photosensitive drum and a process means actable on the photosensitive drum are integrally assembled into a cartridge and this cartridge is made detachably mountable to the image forming apparatus main assembly is employed. In the developing device used in such a process cartridge, in a toner chamber for accommodating a developer (hereinafter referred to as a toner), the toner is directly accommodated.
Further, against a problem such that the toner is scattered in the process cartridge in a developer filling step during manufacturing of the process cartridge, Japanese Laid-Open Patent Application (JP-A) Hei 4-66980 proposes that a deformable inside container in which the toner is confined (hereinafter referred to as a “toner bag” is accommodated in a toner chamber.
However, in JP-A Hei 4-66980, a toner discharging operation after unsealing of the inside container was not taken into consideration. For example, in a constitution in which the bottom of the toner bag is not provided with inclination enough to permit fall (drop) of the toner by its own weight, it was difficult to discharge the toner in some cases. Further, also in a constitution in which an opening for the toner bag cannot be formed in a lower side with respect to a direction of gravitation, there is the case where it is different to discharge the toner.